Water ice and dry ice refrigeration system



Feb. 22, 1938. A. J. coRDREY 2,109,310

WATER ICE AND DRY ICE REFRIGERATION SYSTEM Filed July 3, 1935 Patented Feb. 22, 193s UNITED STATES PATENT OFFICE WATER ICE AND DRY ICE REFEIGEBATION SYSTEM Application July 3, 1936, Serial No. 88,716

Claims.

This invention relates to a refrigeration system utilizing both water ice and dry ice as cooling agents.

' More speclcally this invention relates to the refrigeration of storage spaces in trucks, trailers and the like vehicles by means of two difierent types of cooling agents. one of which serves to precoci the storage space and is used when loading and at the start of a trip and the other of which is lighter and less bulky and is used to maintain the storage space in its cooled condition throughout the rest of the trip.

In my copending application Serial No. 87,881 led June 29, 1936, entitled: Dry ice refrigerating apparatus and method, I have described and claimed a dry ice refrigeration apparatus for vehicles having cold storage spaces. This apparatus includes an insulated container for dry ice, a heat exchanger and a liquid circulation system wherein a liquid having a low freezing point, such as alcohol, is circulated into thermal rela.- tion wih the dry ice in the container to be cooled; the cooled liquid flows through the heat exchanger to absorb heat therefrom, and the warmed liquid from the heat exchanger recirculated back into thermal relation with the dry ice. The air oi the storage space is circulated around the heat exchanger and cooled to maintain the storage space at a desired temperature. I'he air can be cooled to any desired amount by thermostatically regulating the flow oi liquid through the heat exchanger.

According to the present invention a water ice bin or housing is formed either within the body of a truck, trailer or the like or on the roof of the vehicle or on a platform provided on the vehicle. Air from the storage space of the vehicle is circulated around the water ice in the bin, cooled by contact therewith and discharged back to the storage space. This circulation oi' air over the water ice serves to precooi the storage space but due to the great weight of water ice required to maintain the storage space cooled, it is not desired to transport such a heavy cooling agent. Therefore a dry ice refrigerating apparatus, such as is described in my copending application. is used to maintain the precooied storage space cool along the route after the water ice has melted and drained from the vehicle.

It is thus not necessary, according to this invention, to transport a heavy cooling agent or to provide a. large bin for such cooling agent since only enough water ice is used to precool the storage space and if desired to maintain the storage space cool along the first part of the trip.

(Cl. (i2-91.5)

Then, when the water ice has melted, the dry ice apparatus is automatically brought into operation.

It is then an object `of this invention to pruvide a. refrigerating apparatus for vehicles utilzing two different types of cooling agent, the heavier of which is discharged from the vehicle not later than during the rst part of a journey.

A further object of this invention is to provide a. combined water ice and dry ice refrigerating system for vehicles.

Another object of this invention is to provide, in combination with a transport vehicle for heat perishable goods, a bin for water ice having inlet and outlet communication with the storage space of the Vehicle and a dry ice refrigerating apparatus including a liquid circulation system in said bin for maintaining the air of the storage space cool after the Water ice has melted and been drained from the vehicle.

A specific object of this invention is to provide reirigerating apparatus in a transport vehicle for heat perishable goods including a bin for Water ice, an inlet for air from the storage space to the bin, a discharge conduit for air from the bin back to the storage space and a dry ice refrigerating system including a heat exchanger in the discharge conduit for cooling air circulated through the duct after the water ice has melted Other and further objects of this invention will become apparent from the following detailed description of the annexed sheet of drawings which disclose a preferred embodiment of the invention.

On the drawing:

Figure l is a broken side elevational view, with parts broken away and shown in cross-section, of a truck trailer equipped with a refrigerating system according to this invention.

Figure 2 is a vertical cross-sectional view, with parts in elevation, taken substantially along the line II-II of Figure l.

As shown on the drawing:

In Figures 1 and 2, the reference numeral in indicates a truck trailer of theusual type for transporting heat perishable goods, having an insulated roof ii and insulated walls I2 defining a storage space I3 for the goods.

According to this invention a partition wall Iii is disposed in the storage space I3 near the front end thereof to dene with the walls and roof of the storage space a bin I5 for water ice I6. The oor I'I of the bin I5 slopes to a. drain I8 extending through the iloor of the trailer for perniitting the drainage of melted ice from the bin'.

An inlet opening Il is provided through the wall I4 permitting the circulation of air in the storage space I3 into the bin I5. Movable louvers 20 may be disposed in the opening I! to control the inlet capacity of the opening and to direct the incoming air over the ice I2 in the bin.

A duct 2| is provided in the lower part of the bin I5 and communicates with the space 22 between the floor 23 of the vehicle and a false bottom 24 within the storage space I3 of the vehicle. Discharge outlets 25 are provided at various points in the false bottom 24 to distribute cold air from the space 22 into the storage space I3, as will hereinafter be more fully pointed out.

The duct 2| has an opening 28 therein for xecelving air circulated through the opening I9 into the bin. In order to prevent the clogging of the duct 2| with water ice i8, a shield 21 is disposed over the opening 2B. I'his shield serves as a support for water ice IIi disposed over the opening 26 but is spaced from the opening so as to permit the free entrance oi air into the duct.

A fan 28 is rotatably mounted in the duct 2| adjacent the opening 2B therein for propelling air through the duct and into the space 22 between the iioor of the truck and the false bottom of the sorage space. The fan can be conveniently driven by means of a small auxiliary engine 28 through a belt connection 2li. Obviously, of course, an electric motor can be used to directly drive the fan.

An elongated container 3| is mounted within the bin I5 and preferably near the top thereof and can be conveniently supported from a wall I2 of the vehicle by means of a bracket 32. The container 3l houses a liquid receiving tank 33 l Figure 2l preferably formed of metal as is more fully disclosed in my copending application above referred to. Dry ice is disposed over the tank 33 in the housing 2| for cooling liquid within the tank.

A liquid having a low freezing point is placed in the tank 33 and ilowsircm the tank through a pipe line 34 into the inlet header 25 of a heat exchanger 36 located in the duct 2| in front of the fan 28. The liquid then circulates upward through the tubes of the heat exchanger to cool these tubes and absorb heat from air flowing through the duct. The warmed liquid then flows upward by convection and by hydrostatic head of the liquid maintained above the heat exchanger into a discharge header I1 of the heat exchanger and from the discharge header into a pipe line 2B having a thennostatlc valve 29 therein communicating with a pipe line 40 back to the inlet opening of the tank 22 which inlet opening is at a higher level than the discharge opening communicating with the pipe line 24.

The thermostatic valve 29 in the pipe line Il can be adjusted to open at any desired temperature by means of an adjusting device 4I thereon.

The roof I I of the vehicle Il) can be conveniently provided with a removable insulated cover 42 to permit a charging of the bin I5 with water ice IE. The container 2| also has a removable cover or door 43 in one end thereof to permit a charging of the container with dry ice.

The operation of the device is as follows:

Air from the storage space |2 of the trailer Ill enters into the bin I5 through the opening I9, circulates around the water ice I6 in the bin and i: cooled by contact therewith. The cooled air then ows through the opening 2l into the duct lfrom is drained from the trailer through the drain pipe Il.

When the cooling power of the water ice Ii diminishes below a point necessary to maintain the storage space at a desired temperature, air entering the opening III into the bin will be at a temperature higher than that desired. The thermostatlc valve 38 can be set to open at any desired temperature and when the air contacting this valve is at a temperature above that for which the valve has been set, the valve will automatically open thereby permitting circulation of liquid through the heat exchanger 36. This liquid is cooled by dry ice in the container II and the heat exchanger Ill is thus cooled by the cooled liquid.

Air entering through the opening 26 into the duct 2| must pass around the heat exchanger 38 and be cooled by contact therewith.

The fan can be used to increase the circulation pi air through the water ice bin I5 and duct 2|. The dry ice in the container 3| will maintain the storage space I2 at a desired cooled temperature even after all of the water ice I6 has been melted and drained from the trailer.

Obviously many modifications of the above described apparatus are possible without departing from the scope of this invention. For example the circulation of air can be reversed so that the warm air enters the bln I5 at the bottom and the cold air is discharged at the top of the storneed not be solid, but can be made o! spaced slats thereby allowing the cooled air to circulate through the spaces between the slats and rise by convection to th'e top of the trailer. Obviously also a single duct or a series of ducts can be used to distribute the cooled air to the storage space I2.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

l. In combination with a vehicle having a storage space therein. a bin carried by said vehicle and adapted to hold ice therein, means for circulating air from said storage space through said bin and back to the storage space, a dry ice refrigeration apparatus in said bin and means to bring said apparatus Into operation when the air in the storage space is not maintained sufiiciently cool by ice in the bin.

2. In combination with a vehicle having a storage space therein. an insulated bin carried by the bin back to the storage space, a heat exchanger in the path of said air, a dry ice container in the bin, liquid receiving means in the container having inlet and outlet connections with the heat exchanger whereby a liquid is cooled by dry ice in the container, circulated through the heat exchanger to cool the same and is recirculated back into the receiving means and a thermostatic valve in the path of said liquid allowing said circulation only when the ice in the bin has melted or does not have sufiicient cooling power to maintain the air in the storage compartment at a desired temperature.

3. In combination with a vehicle having a storage space therein, an insulated bin carried by said vehicle adapted to hold water ice therein, said bin having an inlet for warm air from the storage space, a duct in said bin for conveying air therein for distribution to the storage space of the vehicle, a heat exchanger in said duct, a dry ice container in the bin, liquid receiving means in the container having inlet and outlet connection with the heat exchanger whereby a liquid is cooled by dry ice in the container, circulated through the heat exchanger to cool the same and is recirculated back to the receiving means and means for regulating the amount of said circulation.

4. In combination with a transport vehicle for heat perishable goods having a cold storage compartment, an insulated bin carried by said vehicle and adapted to hold water ice therein, a duct in said bin having an opening communieating with the interior thereof and an outlet opening communicating with the storage space of the vehicle, a heat exchanger in said duct, means for circulating a cooled liquid through said heat exchanger, means for propelling air thru the bin into the duct around the heat exchanger and back into the storage space of the vehicle and means controlled by the temperature in the bin fo'r regulating circulation of the cooled liquid thru the heat exchanger.

5. In combination with a transport vehicle for heat perishable goods having a cold storage compartment, a partition wall in said cold storage compartment defining a bin adapted to hold water ice, and an inlet opening at the top of said partition wall, a duct in the bottom of said bin communicating with the storage space, said duct having an inlet opening therein. a heat exchanger in said duct, means for circulating a cooled liquid through said heat exchanger, a valve controlled by the temperature of the bin for regulating the now oi' cooled liquid through the heat exchanger, and a fan in said duct for drawing air through said inlet over the water ice into the duct, around the heat exchanger and back to the storage space in a cooled condition.

6. A transport vehicle for heat perishable goods comprising means defining a storage space for said goods, a false bottom in said storage space having a plurality of openings extending therethrough, said false bottom being in spaced relation to the floor of said vehicle to denne a passageway for air, a partition wall in said storage space at one end thereof defining a bin adapted to hold water ice, said partition wall having an inlet opening at the top thereof, a duct in the bottom of said bin having an inlet opening communicating with the bin and a discharge opening communicating with the space between the false bottom and floor of the vehicle. an insulated container in the top o! said bin adapted to hold cry ice therein, a heat exchanger in said duct in uid communication with the container, a fan adjacent said heat exchanger for propelling air to said duct and a motor for driving said fan.

7. In combination with a vehicle having a storage space therein, a bin carried by said vehicle adapted to receive water ice therein having air inlet and air outlet communication with the storage space, an insulated housing carried by said vehicle adapted to receive dry ice therein, a thermally conductive liquid container in said housing having liquid inlet and outlet openings, a heat exchanger in said bin in communication with the inlet and outlet openings of the liquid container for receiving cooled liquid therefrom and a valve controlled by the temperature in the storage space for regulating ilow of liquid between the container and heat exchanger whereby dry ice is utilized to cool the storage space after the cooling capacity of the water ice is diminished beyond an amount necessary for maintaining the storage space below a predetermined temperature.

8. 'I'he method of refrigeration which comprises circulating air into thermal contact with water ice until the cooling capacity of the water ice diminishes beyond an amount necessary to maintain the air below a predetermined temperature and thereafter circulating a dry ice cooled liquid into thermal contact with the air to cool the air.

9. The method of refrigeration which comprises cooling a. space below a predetermined temperature with water ice until the cooling capacity of the water ice decreases beyond the amount necessary to maintain the space below said temperature, utilizing the increased temperature of the space to induce the flow of a liquid cooled by a different agent into thermal communication with the space and thereafter cooling the space with said cooled liquid.

10. The method of refrigeration which comprises cooling a space below a predetermined temperature with water ice until the cooling capacity of the water ice decreases beyond the amount necessary to maintain the space below said temperature, cooling a non-freezing liquid with dry ice, utilizing the increased temperature of the space to induce the ow of the cooling liquid into thermal communication with the space and thereafter cooling the space with said cooled liquid.

ALMON J. CORDREY. 

